Tag Archives: Honey bees

Today some more of my research was published. In it I show that diseased bees deposit parasites on to the flowers they visit. These parasites can then infect healthy bees visiting the same flowers, or be transported by an unsusceptible bee species to other flowers to reach their host species.

I allowed bumblebees from hives infected with three different bumblebee diseases to forage on a patch of flowers in a flight cage for a period of 3 hours before removing them from the cage. Then I released disease-free honey bees into the cage and allowed them to forage for a further 3 hours on the same flowers, as well as a patch of uncontaminated flowers which were brought in at the same time. Immediately afterwards, the shared flower patch, the honeybee only flower patch and the honey bees were all screened for the bumblebee parasites with alarming results. All three of the parasites were detected on the shared flowers, while two out of three were detected on the flowers which only the honeybees had access to, as well as inside the honeybee colonies.

The experiment was repeated using honeybees from hives infected with two honeybee diseases and disease-free bumblebees and yielded similarly worrying results. Both parasites were found on the shared flowers, as well as on the flowers which only bumblebees had access to, and one of the two parasites was detected inside the bumblebee colony.

The study also compared how two different flower types aid the dispersal of bee parasites, and found that bell shaped Fairy’ thimble flowers contained higher parasite loads than more open Pansy flowers. This is likely because the bees spend more time in contact with bell-shaped flowers than they do with more easily accessible open flowers.

These results suggest that flowers play an important role in the transmission of diseases between bees.

“The upshot of this is that a range of parasites in diseased bee populations, such as infectious imported bees, may spread to wild bee populations that forage on the same flowers. On a wider level, flowers as parasite hotspots suggests that areas where there is a lot of pollinator traffic per flower, for example areas with low flower density, may have high parasite dispersal between pollinators compared to areas with low pollinator traffic per flower, such as flower rich areas.”

Mixing with managed bees may be to blame for increased diseases in wild bumblebees, prompting concern for their conservation, scientists have warned. It has been discovered that bumblebees suffer from more parasites when they are collected from around sites using managed bees.

Managed honey bees and bumblebees are frequently used by apiarists and farmers for their honey production or pollination services. The introduction of managed bees can increase the number of pollinators competing for resources in a given area and this can have ramifications to native pollinators.

A. bombi from Argentina and Europe share a common, relatively recent origin. The absence of genetic structure across space and host species suggests that A. bombi may be acting as an emergent infectious disease across bee taxa and continents.

Results from my newly published work, The Trojan hives highlights imported dangers to native pollinators. Over a million commercially produced bumblebee colonies are imported annually on a
global scale for the pollination of greenhouse crops. After importation, they interact with
other pollinators, with an associated risk of any parasites they carry infecting and harming
native bees.

Following 2 years of monitoring, my research has shown how the majority of commercial bumblebee hives we purchased in 2011 & 2012 contained harmful parasites.

We found microbial parasites in 77% of the commercially produced bumblebee colonies we purchased from three producers, which were imported on the basis of being free of parasites. Following this, we found that a number of these parasites were infective and detrimental to both bumblebees and honey bees.

The results demonstrate that commercially produced bumblebee colonies carry multiple, infectious parasites that pose a significant risk to other native and managed pollinators. More effective disease detection and management strategies are urgently needed to reduce the pathogen spillover threat from commercially produced bumblebees.